Plummet

ABSTRACT

A plummet for ascertaining verticality is described, comprising a disc-shaped body having a central aperture. The disc is suspended by means of a line in a position radially parallel to the ground or work surface. Upon lowering it to rest on the ground, marking of the point of verticality may easily be effected at the center of the aperture. The plummet may be used in combination with an accessory plummet disc of substantially the same diameter as the suspendable plummet and which serves as a target to be placed upon the floor or like surface; vertical alignment can thus be ensured when the suspendable plummet is concentric with the target plummet disc.

United States Patent 1 Rollband [451 May 27, 1975 PLUMMET [76] Inventor: Ernest J. Rollband, Green Acres Mobile Home Park, 3415 Slaterville Rd., R.D. No. 1, Brooktondale, NY. 14817 22 Filed: June 25,1973

21 Appl. No.: 373,499

Related US. Application Data [63] Continuation-in-part of Ser. No. 153,282, June 15,

1971, abandoned.

UNITED STATES PATENTS 174,892 3/1876 Beckwith 33/392 2,873,531 2/1959 Chick 3,448,525 6/1969 Majewski 33/392 FOREIGN PATENTS 0R APPLICATIONS 1,960 8/1911 United Kingdom 33/392 Primary Examiner--Richard E. Aegerter Assistant Examinep-Richard R. Stearns [5 7] ABSTRACT A plummet for ascertaining verticality is described, comprising a disc-shaped body having a central aperture. The disc is suspended by means of a line in a po sition radially parallel to the ground or work surface. Upon lowering it to rest on the ground, marking of the point of verticality may easily be effected at the center of the aperture. The plummet may be used in combination with an accessory plummet disc of substantially the same diameter as the suspendable plummet and which serves as a target to be placed upon the floor or like surface; vertical alignment can thus be ensured when the suspendable plummet is concentric with the target plummet disc.

3 Claims, 3 Drawing Figures PLUMIMET This is a continuation-in-part of my pending application, Ser. No. 153,282 now abandoned filed on June 15, 1971.

This invention relates to plummets or plumb lines which find extensive use in determining the verticality to ground by virtue of gravitational force. Plummets, in general, consist of relatively heavy bodies having a conical shape with a pointed end. The latter serves as the indicator for locating the spot to which the suspension point of the plummet bears a vertical relationship.

These conventional type plummets have the draw-' back that, in order to mark the desired spot, it is necessary to firmly suspend the plummet from above with the pointed end close tothe ground. Upon reaching stability, the person using it must practically lie flat on the ground in order to give a close estimate of the spot located directly beneath the pointer. In order to expedite work, two persons are needed one to hold the plummet suspended and the other to gauge the position and effect marking.

The operation in reverse, however, is far more difficult. Given the spot at which, let us say by way of exam ple, a post is to be positioned, extending vertically to a cross beam, the person must move the suspension line along the beam and attempt to sight the pointer of the plummet to the desired spot. Here again, two are needed for the job. The person at the top cannot see the pointed end. The one at the bottom must gauge this a time-consuming, hit-and-miss type of procedure. Of course, one may lower the conventional plummet just enough that the pointed end touches the ground. However, on a relatively smooth surface, the pointed end is apt to slide so that the true vertical is no longer indicated.

A variety of plummets constructed along conventional lines are to be found in the prior art. Only one reference, namely, British Pat. No. I960 dated 1911 describes the idea of utilizing a body of ring-shaped construction to be suspended so as to enable the viewing of the center of the ring. No illustration as to the particular construction of such a plummet is given.

The present invention is directed to plummets of the above general type, but of improved construction, permitting greater facility of use.

It is accordingly a particular object of this invention to eliminate the above difficulties by providing a plummet of novel shape which is simpler and easier to manipulate.

It is a salient feature of the invention that the plummet constructed in accordance therewith is inherently more accurate as to the location of the point of verticality.

A particular advantage of the plummet herein described is that only one person is needed for its effec' tive use in either direction, including the sighting from above of a predetermined location on the ground.

Other objects, features and advantages will be appar ent from the following description of the invention, pointed out in particularity in the appended claims, and taken in connection with the accompanying drawing, in which:

FIG. 1 is a top view of the plummet in the form of a disc-shaped body.

FIG. 2 is a perspective view of the plummet shown in FIG. 1, illustrating also the suspension lines attached thereto.

FIG. 3 is a top view of an accessory plummet disc used in one mode of the present invention.

Referring to the figures, as can be seen, the plummet in accordance with this invention comprises a flat discshaped body 10 of relatively heavy material, preferably lead. The disc has a central aperture 11 of comparatively large size in order to accommodate radially. inwardly-extending guide rods 14, 15, 16 and 17 which point toward the center of the disc 10. The length of the rods are so chosen as to terminate near the center, leaving sufficientspace for the user to utilize a marking instrument such as a pencil or a scribe to complete the lines where the rods would intersect.

Eyelets 20, 21 and 22 are affixed to the surface of the disc 10, equidistantly distributed to accommodate a string or chain 25 for the suspension of the disc 10 from a line 26. This is illustrated in the perspective view of FIG. 2.

Regarding the use of the disc-shaped plummet, it will be evident that, properly suspended in a position radially parallel to the surface, it may easily be lowered to the ground, once swinging has stopped and stability has been reached, so that it will rest on the ground. This condition can be arrived at quickly by letting the disc touch ground several times in succession. Once the spot has been found where lifting produces no swing, it can then be lowered to stay on the ground. It need not remain in a suspended state thereafter since the lower surface is substantially flat: and accordingly it will lie flat on the ground and the person may mark the center point with ease.

Even simpler and more efficient is the use of the plummet herein described in the reverse direction. For this purpose, two plummets of similar construction are employed one as an accessory, having no suspension means so that both sides are flat as seen in FIG. 3. In the illustrated embodiment the: accessory plummet disc generally designated by the numeral 100 is of the same configuration as the principal plummet disc 10 with a central aperture 111 of the same size and with pointer elements 114, 115, 116 and 117 to facilitate coaxial alignment. One plummet is held in suspension above the floor and manipulated to descend neatly over the accessory plummet on the floor in coaxial relation until the two discs touch. The suspension point thus will be directly perpendicular to the selected spot so that the user may then mark the location of the suspension line.

As can be seen, for either manipulation, only one person is needed inasmuch as, in either direction of use, the disc plummet is lowered until firmly resting on the ground. The person utilizing it from a fixed position above may discard the suspension and effect markings by the guiding means with which the plummet is equipped. In the reverse position, once coaxial position has been established, he simply marks the place of the suspension line.

In practice it was found that lead offered the best material for satisfactory weight and that rods made of brass provided sturdy construction and sufficient distinction for observation by the person holding the plummet in suspension. Obviously the body of the plummet and the indicating rods may be painted in different colors to further enhance the distinction.

In a practical embodiment, the size of the plummet was 2V2 inches in diameter with a central aperture of 1% inches. Four rods displaced at an angle of from each other were used and gave excellent results.

an inner wall of said body defining a central aperture.

a plurality of pointers on said inner wall extending toward the center. of said aperture defining the center of gravity of said disc-shaped body, said pointers indicating the center at the intersection of the imaginary lines drawn therethrough; and suspension means for said disc-shaped body on the upper surface thereof for holding said body in position parallel to the work surface, the flat lower surface of said body being adapted for stable seating upon a substantially planar support surface; and an accessory plummet disc comprising a discshaped body having substantially flat upper and lower surfaces and substantially of the same diameter as the disc-shaped body of said suspendable plummet said suspendable plummet being alignable with said accessory plummet disc disposed upon a reference surface and functioning as a target therefor.

2. The plummet assembly in accordance with claim 1 wherein said accessory plummet disc has a central aperture defined by an inner wall of the body thereof of the same dimension and configuration as the central aperture of the disc-shaped body of said suspendable plummet.

3. The plummet assembly in accordance with claim 2 wherein said accessory plummet includes a plurality of pointers on the inner wall extending toward the center of said aperture therein defining the center of gravity of said disc-shaped body. 

1. A plummet assembly including a suspendable plummet comprising a disc-shaped body with at least the lower surface of said body being substantially flat, an inner wall of said body defining a central aperture, a plurality of pointers on said inner wall extending toward the center of said aperture defining the center of gravity of said disc-shaped body, said pointers indicating the center at the intersection of the imaginary lines drawn therethrough; and suspension means for said disc-shaped body on the upper surface thereof for holding said body in position parallel to the work surface, the flat lower surface of said body being adapted for stable seating upon a substantially planar support surface; and an accessory plummet disc comprising a discshaped body having substantially flat upper and lower surfaces and substantially of the same diameter as the disc-shaped body of said suspendable plummet said suspendable plummet being alignable with said accessory plummet disc disposed upon a reference surface and functioning as a target therefor.
 2. The plummet assembly in accordance with claim 1 wherein said accessory plummet disc has a central aperture defined by an inner wall of the body thereof of the same dimension and configuration as the central aperture of the disc-shaped body of said suspendable plummet.
 3. The plummet assembly in accordance with claim 2 wherein said accessory plummet includes a plurality of pointers on the inner wall extending toward the center of said aperture therein defining the center of gravity of said disc-shaped body. 